Over the years, a substantial number of devices have been developed which will automatically fix a gate against movement from its closed position until some specific action is taken by an operator. One such structure has employed a latch body which may be mounted adjacent the free or swinging side of a gate. The latch body cooperates with a latch strike mounted on a post adjacent the free end of the gate in close proximity to the body when the gate is closed. A latch bolt or locking bar extends through the body in such a manner as to cooperate with the latch strike. Such latching bolts have been pivotally mounted in the bodies for vertical movement about an axis in order to allow the bolt to fall into, and be removed from, a slot in the latch strike as the gate is closed or opened. Thus, when the bolt is in the slot of the latch strike, the gate will not open until some action is taken to pivot it out of the slot. This may be accomplished, for example, by means of a thumb-actuated lever which extends through the gate to lift the bolt from the slot as the thumb lever is depressed. Alternatively, the free end of the bolt may be depressed by an opertor so as to raise the latching end from the slot.
When desired to lock the gate, the latch bolt may be slid horizontally through the body and thus extended through a locking slot in the latch strike which is so formed as to positively prohibit lifting of the latch bolt from the latch slot in the strike.
Such a device has been shown, for example, in U.S. Pat. No. 2,794,663. In that device, it was found necessary to provide a 90.degree. twist in the latch bolt in order to produce a vertical portion of the bolt which could cooperate with the latch and locking slots in the strike as well as a horizontal section which would provide a pivot axis and a handle for pivoting the bolt about its axis. In other words, some method of production had to be employed to extend the bolt part way through the body, produce a 90.degree. twist about the longitudinal axis thereof, and then move it through the remainder of the body. The use of this method also positively prohibited the bolt from being drawn out of the body in either direction. Unfortunately, this structure required a production step which is relatively difficult and expensive to accomplish, even if lightweight material is used for the locking bar.
In order to prevent the inadvertent horizontal movement of such a prior art latch bolt, a plurality of locating notches had to be formed in one edge of the horizontal portion of the bolt to cooperate with a corresponding edge of a slot in the latch body through which the bolt passed. Thus, when one of the notches cooperated with the body, the gate would only latch upon closing and could be unlatched from either side thereof. In an alternative position, a second notch would cooperate with the body to prohibit horizontal motion of the bolt, thereby locking the gate securely since the bolt would be cooperating with the locking slot in the latch strike to prohibit pivoting of the bolt.
In order to prevent inadvertent horizontal movement of the bar from one notch position to the other, a leaf spring had to be provided which would urge the bolt in a direction such that the notches would tend to cooperate with the edge of the slot in the body. Thus, not only was additional structure required to retain positive notch-body cooperation, but the assembly of these elements of the structure was again rather difficult and costly.
Further, because of the twisting required in the locking bar and the ultimate position of the latch handle formed on the bolt, such devices could most suitably be employed only on a right-handed gate or a left-handed gate, depending upon manufacture, and could not be interchanged from one such gate to the other.